Biology: Introduction to Life PDF

INTRODUCTION TO LIFE BIOLOGY = the study of life HIERARCHY of BIOLOGICAL ORGANIZATION  These are all levels at which life may be observed/studied o Subatomic Particles o Atoms o Molecules & Compounds o Subcellular Organelles o...

INTRODUCTION TO LIFE BIOLOGY = the study of life HIERARCHY of BIOLOGICAL ORGANIZATION  These are all levels at which life may be observed/studied o Subatomic Particles o Atoms o Molecules & Compounds o Subcellular Organelles o Cell (lowest level capable of exhibiting all properties/characteristics of life) o Tissue o Organ o Organ System o Multicellular Organism o Population o Community o Ecosystem o Biome o Biosphere CHARACTERISTICS of LIFE  The following are characteristics associated with life/living organisms 1.) Cells o Cell History:  Anton Van Leeuwenhoek (early 1600’s)  First to view microorganisms with a microscope  Robert Hooke (1665)  First person to coin and use the term “cell”  Mathias Schleiden & Theodore Schwann (1839)  Developed the “Cell Theory” (3-parts) 1. All living things are composed of one or more cells 2. All cells come from pre-existing cells  3. The cell is the smallest living entity o Cell Types (2): 1. Prokaryotic Cells  More primitive (older; evolved first)  Typically Much Smaller  No Membrane-bound Organelles, including a nucleus  Examples: Archaeans and Bacteria 2. Eukaryotic Cells  More advanced (evolved more recently)  Typically Much Larger  Have Many Membrane-bound organelles, including a nucleus that contains the genetic material (DNA)  Examples: Protists, Plants, Fungi and Animals o Cellular Features In-common (4):  All cells have the following four features in common: 1. Plasma Membrane – defines the outer boundary of living material. 2. Cytoplasm – everything between the plasma membrane and nucleus. 3. Ribosomes – synthesize proteins. 4. Genetic Material (DNA) – contains the instructions for building proteins. o Cellular Arrangement (3-possibilities): 1. Unicellular Arrangement – entire organism consists of a single cell 2. Colony/Colonial Arrangement o Multiple cells o Typically no contact between cell membranes o No cytoplasmic exchange occurs o Little if any cellular specialization 3. Multicellular Arrangement o Multiple cells o Plasma membranes are interconnected o Cytoplasmic exchange occurs o Typically there is a high-degree of cellular specialization CHARACTERISTICS of LIFE (continued): 2.) Movement 3.) Order 4.) Respond to Stimuli o Stimulus = any chemical/physical change in the internal/external environment of a cell/organism  Example: Homeostasis – the ability of a cell/organism to maintain a constant internal environment regardless of the surrounding conditions. 5.) Energy Utilization o The energy flow for a typical terrestrial or aquatic ecosystem is as follows:  Sun (ultimate source of energy)   Autotrophs (“self-feeders” or “producers” Ex: plants)   Heterotrophs  “Primary Consumer” or “Herbivore” (Ex: grasshopper)   “Secondary Consumer” or “1st Level Carnivore” (Ex: Bird)   “Tertiary Consumer” or “2nd Level Carnivore” (Ex: snake)   “Quaternary Consumer” or 3rd Level Carnivore” (Ex: Coyote)  “Decomposer” (Ex: Bacteria/Fungi)  Radiating back into Space in the form of heat Sunlight  Autotrophs (producers)  Heterotrophs (consumers)  DecomposersOuter Space 6.) Reproduction 7.) Growth & Development 8.) Evolve & Adapt BIODIVERSITY  Approximately 1.8 million species (distinct life forms) have been named and described  An estimated 10-100 million species are believed to exist  Taxonomy – the branch of biology that deals with classifying and naming organisms o Carl Linne’ – (“Father of Taxonomy”) - developed a “Binomial System of Nomenclature” TAXONOMIC HIERARCHY (8-Basic Levels) DOMAIN (least specific / most inclusive) KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES (most specific / least inclusive)  Scientific Name = the genus and species of an organism (Ex: Quercus rubrum = Red Oak)  The taxonomic hierarchy indicates how closely related two organisms are; the more levels they share in-common, the more closely related they are. o Two organisms that are located together in a less specific taxonomic level may also be together in a more specific level but they don’t have to be. o Two organisms that are located in a more specific taxonomic level have to also be located in all of the less specific levels. Example: if two organisms are in the same taxonomic “Class,” they may or may not be in the same “Family,” but they have to be in the same Domain, Kingdom, and Phylum. DOMAINS & KINGDOMS Domain: Archaea (ancient prokaryotes) Domain: Bacteria (modern prokaryotes) Domain: Eukarya (all eukaryotes) Kingdom: Protista (unicellular, colonial, or simple multicellular organisms) Kingdom: Plantae (multicellular photoautotrophs) Kingdom: Fungi (multicellular absorptive heterotrophs)  Kingdom: Animalia (multicellular ingestive heterotrophs) SCIENTIFIC METHOD  The “Scientific Method” is a step-wise process used to derive answers to questions.  Six (6) Steps: 1.) Make an Observation 2.) Ask a Question 3.) Form a Hypothesis (using “inductive” reasoning) 4.) Make a Prediction (using “deductive” or “if-then” reasoning) 5.) Test the Hypothesis (experimentation; must be repeatable) 6.) Draw Conclusions